It will be "at least several months, possibly another six or seven months," before the Department of Defense will be able to launch any large satellites in the wake of the Titan 34D explosion last Friday, according to Donald C. Latham, the assistant secretary of defense for communications, command, control and intelligence, who oversees the nation's military satellite programs.

Latham confirmed that the Challenger disaster and the destruction of the Titan rocket and its secret military payload at the Vandenberg Air Force Base leave the United States without any way to place large satellites in orbit.

Such military satellites, which often contain sophisticated surveillance and reconnaissance equipment, are an integral part of the nation's ability to monitor Soviet military capabilities and determine compliance with various arms control agreements.

Government and congressional sources confirm that the satellite destroyed was an intelligence satellite. Some experts outside the government say it was a KH11 photographic satellite that would have been launched into polar orbit around the earth. The satellite is capable of taking high-resolution pictures and beaming them to ground stations. Other sources indicate it may have been a less capable photo intelligence satellite or even an electronic communications intercepter.

The $65 million Titan exploded seconds after liftoff, the second Titan 34D failure in a row after seven successful launches. The last Titan launch failed in August, destroying its $500 million KH11 satellite payload. The U.S. reportedly now has only one KH11 satellite in orbit.

"We've never had anything like that before," said Latham, "[This last Titan] was carefully prepared because of the last failure . . . it's really an enigma.

"It just goes to show how risky getting into space is."

Latham said that he did not yet know the cause of the explosion or whether there were any inherent problems with the Titan as a launch vehicle. He said that "if it was the solid rocket booster that failed [the part that failed on the Challenger], it would be the first time on the Titan."

Latham reemphasized the Defense Department's new policy of using the shuttle primarily to launch "unique" satellite payloads while relying on "expendable launch vehicles" to put more conventional satellites in orbit.

The Pentagon is retrofitting several of its satellites, such as the global positioning satellite, so they can be launched by booster rockets rather than the space shuttle.

"Every launch vehicle we have is spoken for," said Latham, who anticipates that the Pentagon will have to double its scheduled launches of military satellites in future years.

There is a backlog of at least 10 satellite launches, he said.

But Latham flatly denied speculation that the Pentagon might request on national security grounds that the shuttle be used to launch satellites before its redesign is completed.

"No way," he said.

Latham pointed out that a new "complementary, expendable launch vehicle" to lift heavy payloads is scheduled to go into operation in 1988, "thanks to Cap Weinberger's insistence that we not be completely dependent on the shuttle."

"If we hadn't gotten that through," Latham said, "we wouldn't have a [large satellite launch alternative] until 1990 . . . .It took incredible amounts of political pressure to get that."